Histologia intestinal, parâmetros ósseos e deposição mineral na gema dos ovos de galinhas alimentadas com minerais complexados a aminoácidos

Abstract

Complexed minerals are better absorbed in the intestinal mucosa, as they use the absorptive pathways of the molecules that complex them, with no competition with other minerals, presenting greater bioavailability than non-complexed minerals. The objective was to determine the effect and the levels of total substitution of inorganic sources of Zn, Mn, Cu and Fe by sources complexed with amino acids in the feeding of light laying hens in the production phase. 400 commercial laying hens of the Lohmann White lineage, aged 78 to 98 weeks, were used. The birds were housed in 40 cages, with a capacity of 10 birds / cage. The research lasted 140 days, divided into five cycles of 28 days each. Four diets were used, with total replacement of the non-complex mineral source (NCM) by mineral source complexed to amino acids (AACM), with reduction of the level of supplementation of the mineral levels as being: T1- Control diet, only with NCM; T2- Diet supplemented with AACM and inclusion of 70% in mineral levels; T3- Diet supplemented with AACM and inclusion of 50% in mineral levels and T4- Diet supplemented with AACM and inclusion of 40% in mineral levels. The data were submitted to the Dunnet test, comparing diets with NCM and AACM, one by one. Then, an analysis of orthogonal contrasts (linear or quadratic) and of interests was carried out, at 5% probability (p <0.05), with the aid of the statistical program SAS version 3.1. Histology indicated variations in level and mineral source in all intestinal segments. In the duodenal portion, the source and mineral level influenced the height and width of the villus, with lower values with the inclusion of 70% AACM. In the jejunum the source influenced the height and width of the villus and the depth of the crypt, while the level influenced the widths of the villus and the crypt, with wider villi with NCM. In the ileum, the source influenced the villus width, crypt depth and width, villus: crypt ratio and area, while the level influenced the villus height and width, crypt depth and width and villus: crypt ratio, with linear increase for villus ratio: cypta the measure that reduced the supplementation with AACM. Satisfactory results were observed for all intestinal portions with AACM supplementation. In the densitometry there was influence of the mineral source used, presenting higher densities in general and in the medial portion for the diet with 40% AACM, demonstrating greater resistance and maintenance of bone characteristics. There was no effect of the source on the mineral composition of the tibia, however, higher Ca and P ratios were observed for diets supplemented with AACM. In the buds there was influence of the source and the mineral level in the depositions of Mn and Cu, being possible to observe a linear reduction in the mineral deposition as it reduced the inclusion of AACM. Therefore, the inclusion of up to 50% in the supplementation of complexed sources of Zn, Mn, Cu and Fe in total replacement of non-complexed sources, provided better histological conditions, positively influencing the villus: jejunal and ileal crypt relationship, and yet, throughout intestinal absorption surface area, as well as better bone parameters, showing no damage as to the micromineral deposition in the yolk.